Dr Paul Kelly is a physical activity and public health epidemiologist. He has been a lecturer in physical activity for health at the University of Edinburgh since August 2014, and has previously worked at the University of Oxford where he completed his PhD using wearable cameras to test the measurement properties of active travel diaries.
Here he gives an overview of some of the work he has been involved in to calculate the economic benefits from walking and cycling.
We know that physical activity is vital for our health and well-being. It is known to promote physical and mental well-being and to prevent or help treat many non-communicable (chronic) diseases such as cardiovascular disease, coronary heart disease, diabetes, stroke, depression and dementia. Walking and cycling (known as active travel) are great ways to be physically active. A major challenge is how do we accurately quantify or measure walking and cycling levels, and effectively communicate the resulting benefits. In particular, we need to get better at convincing people (especially decision makers) that it is worth investing in designing our environment to increase active travel.
The evidence we collect to do this covers a number of aspects, such as the magnitude of the health benefits, the strength of influence of the environment and the success of interventions designed to increase walking and cycling. All of this fundamentally relies on good measurement. Therefore efforts to improve these measurements will give us more confidence in the evidence generated.
There are three main ways to measure physical activity behaviours such as walking or cycling:
- We can ask people what they did recently, or what they normally do.
- We can ask them to wear a device like a pedometer or GPS (Global Positioning System) monitor to record what they do.
- We count pedestrians or cyclists on important routes or junctions.
At the moment we know that there are errors in these different methods, and this limits our ability to understand the scale of the benefits, or know what environmental interventions work the best.
My research interests revolve around understanding the strengths and weaknesses of these methods. This in turn allows us to assess the quality of evidence generated and select the best tool for different research questions.
The Health Economic Assessment Tool (HEAT)
My interests in measuring active travel and the resulting benefits led me to be involved in the Health Economic Assessment Tool (HEAT) for walking and cycling. This is a World Health Organisation (WHO) led project to go beyond quantifying the health benefits. They instead try to estimate the economic benefits that occur when more people walk and cycle, and health improves. By quantifying the health benefits in economic terms, we might be able to be better advocates and influence transport and travel planning decisions to reduce motor vehicle travel, and increase walking and cycling levels.
The tool allows the user to answer two types of important questions:
- What is the current economic value of active travel? e.g. If x number of people in Scotland walk an average of y distance to work on z days in a year, what is the economic value of the health benefits that result from this behaviour?
- What is the economic value of an intervention to encourage active travel? e.g. If Edinburgh builds cycle paths that get x new cyclists completing y miles every week, what is the economic value of the health benefits that result from this behaviour change?
In both cases the user is required to input estimates of how much walking or cycling the population of interest is doing, which is where my interest in measuring these behaviours to provide these data comes in.
The tool has proved very popular globally with nearly 100 documented applications from cities, national governments, researches, practitioners and active mobility advocates, including 14 government or policy guidance documents and 28 academic papers.
Transform Scotland, for example, calculated that if 40% of Scottish car commuter journeys of less than five miles in length were switched to cycling, the economic benefit (accruing after five years) would be £2 billion per year. At a more local level, the Glasgow Centre for Population Health used HEAT to estimate that the mean annual benefit of cycling levels in the city was over £4 million in 2012. It’s important to note as well that HEAT estimates are considered conservative as the tool only accounts for reduced mortality (deaths) and not reduced morbidity (diseased state) or other health benefits associated with cycling.
Leave the car at home
For members of the public the message is simple: as often as possible leave the car at home and walk or cycle to your destination, especially for journeys of less than one mile! This is great if you can do it for routine journeys such as the school run or commuting. Public transport use can also be good as there are opportunities to walk and cycle as part of the journey.
Of course, there are more than just health benefits from encouraging this move out of cars, and this is where we find the link to SEPA’s work. There are clear environmental benefits from increased walking and cycling, and reduced motor vehicle use. HEAT adds to this argument by providing an easily understood source of evidence when trying to influence public opinion and policy decisions.
In this way we can move towards an integrated travel and transport policy that makes walking or cycling the easier, more enjoyable, and cheaper way to travel on a daily basis.
Follow Paul on Twitter: @narrowboat_paul